Python print函数的format()方法的使用

1.使用'{}'占位符

>>> print("{} {}".format('Hello','world'))
Hello world
>>> print("He is a {} years old boy".format(19))
He is a 19 years old boy

2.使用'{0}' '{1}' 索引形式的占位符，这种方式可以改变占位符的位置

>>> print("{0} {1}".format('Hello','world'))
Hello world
>>> print("{1} {0}".format('Hello','world'))
world Hello

3.使用'{name}'形式的占位符

>>> print('His name is {name}, a {age} years old boy'.format(name='LCF',age='19'))
His name is LCF, a 19 years old boy

4.混合使用索引和名字的形式

>>> print('{0},I\'m {1},{message}'.format('Hello','LCF',message = 'This is a test message!'))
Hello,I'm LCF,This is a test message!

5.其他应用

>>> import math
>>> print('The value of PI is approximately {}.'.format(math.pi))
The value of PI is approximately 3.141592653589793.
>>> print('The value of PI is approximately {!r}.'.format(math.pi))
The value of PI is approximately 3.141592653589793.
>>> print('The value of PI is approximately {0:.3f}.'.format(math.pi))
The value of PI is approximately 3.142.
>>> table = {'Sjoerd': 4127, 'Jack': 4098, 'Dcab': 7678}
>>> for name, phone in table.items():
... 	print('{0:10} ==> {1:10d}'.format(name, phone))
... 
Sjoerd     ==>       4127
Jack       ==>       4098
Dcab       ==>       7678